Drum construction



3 Sheets-Sheet 1 :o o o o 2 LIV c. J. PETERSON DRUM GQNSTRUCTION Filed Jan. 26, 1940 3mm Clarence JPeterson Nov. 18, 1941.

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DRUM CONSTRUCTION s Sheefs-Sheet 2 Filed Jan. 26, 1940 C'Zafence JPeirson 1941- c. J. PETERSON DRUM CONS TRUGTION Fi'ledJan. 26, 1940 s Sheets-Sheet '5:

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. Clarence" JPeierson Patented Nov. 18, 1941 DRUM CONSTRUCTION Clarence J. Peterson, Salt Lake City, Utah, as-

signor to The Eimco Corporation, Salt Lake City, Utah Application January 26, 1940, Serial No. 315,729

6 Claims.

My invention relates t improvements in drum construction for vacuum filters of the drum type and for other structures of a similar nature.

The general practice, according to the present state" of the art in the construction of the framework of drums, is to use an extremely heavy center shaft upon which at intervals between the end trunnions is mounted a number of intermediate spaced spiders. To the outer peripheries of the spiders are secured the staves or metal plates that form the base structure for the drainage system which is also bolted into the filter drum. Many expedients have been used to brace and bolster this construction, including the use of truss rods.

With a view to producing as large a filter as possible, thus necessitating long spans between trunnions, it has been inevitable that the center shaft will deflect because of its own weight and the imposed weight entailed in the construction under the present art. This deflection in a combination with the rotation of the filter produces a Wave of distortion that is transmitted by the spiders to the drum and it makes difficult the maintenance of a close, even contact on the drum face by the cake discharge scrapers.

This distortion or deflection also subjects all vacuum connections on the drum to undue stress and strain, and'in a relatively short time leakage occurs that impairs the efficiency of the Continued use of a filter drum which is distorting itself aggravates the unfavorable conditions, raises the cost of maintenance because of increased wear and tear on the filter covering and on the other parts, including the trunnions sive coatings of. the solids in the pulp solution accumulate on the parts of the drum immersed in the solution and they build up until the dead load carried by the drum becomes an important factor in increasing the power consumption nee-- essary to rotate the filter.

The installation of drum filters of this class has become an assembly operation on the sight where the filter is to be used because ofthe impossibility of shipping. large-sized assembled Under the method of construction in which 55 the drum head spider,

are employed the intermediate spider units supported upon the central shaft, the very utmost of care is required in matching the outer rims of the spider so that they are true to shape and absolutely concentric. After the machine has been knocked down and then reassembled, it is not always possible to replace the parts in exactly the same arrangement as before and the filter is occasionally out of line. In addition, the deflection caused by sagging before mentioned, which occurs along the center shaft, nullifies every attempt made to insure the true cylindrical drum concentric with its supporting shaft.

The principal objects of this invention, therefore, are to provide a method of constructing filter drums which in their ultimate installation have a true cylindrical shape; to provide a drum construction for open head drums which will permit a free under flow of pulp while the filter rotates with a minimum of structural members upon whcih the pulp may accumulate; to provide a filter construction method for drums which readily lends itself to the routineof factory fabrication and assembly and is still capable of being knocked down and reassembled by relatively unskilled labor at the point of ultimate use; to provide a filter drum construction wherein all internal and external stresses and loads on the drum are transferred directlyto the trunnions and their journals, thus obviating the necessity of carrying undue weights on. long spans of the central shaft; other objects and advantages of the invention will be apparent during the course of the following description.

In the drawings forming a part of this specification and in which like numerals designate like parts throughout the same,

Figure l is a longitudinal cross sectional View taken through the filter drum assembly substantialiy on line l"l of Figure 2,

Figure 2 is a transverse sectional view taken on line 2-2 of Figure 1 with parts broken away for convenience of illustration,

Figure 3 is a perspective view of a portion of Figure 4is a perspective view of a segment forming a part of the annular section ring.

Figure 5 is a perspective view of a portion of one end of a girder or longeron used in my method of construction,

Figure 6 is a fragmentary transverse sectional View taken on line 6-6 of Figure 1, and

Figure 7 is a fragmentary detail view illustrating an alternate or modified form of construction of the long-rons.

Referring now to Figure l, the numeral l l designates the drive trunnion having annular flanges l2 and an attaching web |3 on its inner end. Secured to the outer end of the trunnion is the attaching plate M for the reception of the wear plate of the automatic valve which has not been shown in the drawings. A central tubular shaft |5 having a flange I6 is bolted to the web l3 by means of the bolts At the opposite end of the shaft |5 is a second flange N! that is bolted to the web or head I9 of the trunnion 20. The outer end of the trunnion 20 is closed by means of the plate 2|. Bolts 22 attach the flange l8 to the head |9. The trunnion 20 has an attaching flange l2 of a similar nature to that employed in connection with the trunnion Drum head segments 23, illustrated in Figure 3, comprise inner-attaching flanges 24, bifurcated segment legs 25, and the segmentary rim sections 26. The flanges 24 of the drum head segments are bolted to the annular trunnion flanges l2 by bolts 21, which pass through the bolt holes 28 and the flanges 24 and match holes in the flanges l2.

The usual assembly of a drum head of this nature consists in mounting the trunnions I I and 20 on the single tubular shaft, which has been secured thereto in the journals provided in the primary supporting structure of the filter unit. When the drum head segments 23 have been all bolted or otherwise secured in place as above described, the girders 28, having gusset plates 29 on each end, are fastened between the outer ends of the legs 25 of each segment by bolts or rivets.

In Figur 5 I have shown the girder to have holes 30 punched through the web of the structure shape forming the girder in order to lighten the weight, and the use of these holes does not materially decrease the strength of the girder for the purpose to which I put it.

In Figure '7, wherein is shown a modified form of girder construction, the girder 3| has been formed in the double lattice truss by slitting the web of the structural shape and expanding it as shown, and a knee or gusset 32 has also been illustrated for the purpose of providing increased strength at the point of attachment of the girder to the drum head segments.

Annular section rings 33 are illustrated in Figure 4 as having a web 34 and opposed flanges 35. Each section 33 at its ends has flange plates 36, and a number of these bolted together form a complete annular ring. U-shaped clips 31 having slots 38 are fastened to the web 34 and flanges 35 at suitable points around the inner face of the ring and are secured to the girder 28 or 3| by means of the bolt 39, whose head 40 engages the" inner face of the slot 38. A nut 4| tightens the bolt of the clip 31 to the flange of the girder member. Suitable truing shims are indicated at 42.

When the desired number of annular rings, shown to be three in number in Figure 1, are anchored in place, the decking or drum staves 43 are anchored to the outer periphery of the segmental drum heads and to the annular rings by means of hook bolts 44 and nuts 45, which are usually counter-sunk into depressions such as 46. Splines 41 are quite often used between the staves 43 to assure a tight surface on the outer face of the drum.

When the assembly has reached this stage, suitable connections are made to the segments of the drum face for the application of the vactaken as a preferred example of the same, and

uum or compressed air thereto, and the filter screen or filter surface is applied. Suitable drive means may be connected to the trunnion II, as well as a suction valve, which I have not deemed necessary to illustrate in this application as it forms no part of the invention.

Filler pieces 48 are usually bolted between the inner ends of the legs 25 between each segment in order that a space is provided at their outer ends for the accommodation of the gusset or knee 29 of the girder.

It will be apparent from the foregoing description that as the drum revolves, the only elements immersed in the solution being filtered are the drum facing and its filter surface, the outer ends of the legs of the drum head segments, the girders, and such tubular elements as may be necessary in the drainage system to convey the liquids from the face of the drum to the tubular shaft l5, from whence it is discharged through the trunnion After the drum has been completely fabricated, marked for matching, and torn down for shipment, it is a relatively simple job and requires little space for it to be reassembled and to be ready for use for filtering. The annular rings which encircl the girders intermediate of the drum heads are attached in place with ease and convenience, and any truing that may be necessary is accomplished by fitting shims 42 under the inner faces of the clips 31, as well as shims 49 between the flange plate 36 of the annular ring sections 33. Bolts 50 having nuts 5| secure the flange plates together in a conventional manner.

According to the principles of my invention as herein described, it is to be pointed out that when the filter drum is completely constructed, its entire weight is carried on the trunnions H and 20, and is transmitted from the central portion to the drum and thence to the trunnions through the girders 29, or through the modified form designated by the numeral 3|.

It is to be understood that the form of my invention, herewith shown and described, is to be that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention, or the scope of the subjoined claims.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A drum construction for filters comprising a central shaft having a trunnion secured to each end and adapted to be supported in suitable journals, circular drum heads attached to said trunnions, longitudinally extending girders spaced apart from each other and secured at their ends to said drum heads, annular ring members secured outside said girders intermediate said drum heads and wholly supported thereby, and an enclosing decking mounted on the rims of the drum heads and of the intermediate ring members.

2. A drum construction for filters comprising a tubular central shaft having a trunnion at each end adapted to be supported in suitable journals, circular spider heads attached to said trunnions, longitudinally extending girders spaced apart from each other and secured at their ends about said drum heads, annular ring members mounted outside said girders intermediate said drum heads and wholly supported thereby, and an enclosing decking mounted on and connected at their ends about the drum heads, annular ring members having notched inner attaching clips for engaging the head of a bolt carried by the girders, said rings secured outside said girders intermediate said drum head segments, and being wholly supported by said girders, and an enclosing decking supported on the rims of the drum heads and the annular ring members.

4. A drum construction for filters comprising a central shaft having end flanges and an annularly flanged trunnion secured to each flange, said trunnions adapted to be supported for rotation in suitable journals, circular drum heads comprising a multiple number of drum head segments secured to the annular flanges of each trunnion radially of the axis thereof, longitudinally extending girders connected at their ends to the drum heads and spaced apart thereon, annular ring members secured outside the girders intermediate of and wholly supported by said drum heads, and an enclosing decking on the rims of the drum heads and the annular rings.

5. A drum construction for filters comprising ,a central shaft having an annularly flanged trunnion secured to each end and adapted to be mounted in suitable journals, a pair of circular drum heads each comprising a multiple number of drum head segments attached to the annular flanges of a trunnion radial of its axis, each segment comprising anvattaching flange having a pair of substantial radial legs and an outer cone necting rim section, longitudinally extending girders spaced apart from each other and connected at their ends to the drum heads, annular ring members secured to said girders intermediate the drum heads and Wholly supported thereby, and an enclosing decking supported on the rims of the drum heads and ring members.

6. A drum" construction for filters comprising a central shaft having an annularly flanged trunnion secured to each end and adapted to be mounted in suitable journals, a circular drum head attached to the flange of each trunnion radial of its axis and comprising a multiple number of abutting drum head segments, each having a pair of substantial radial legs and a connecting rim section between the outer ends of the legs, longitudinally extending girders spaced apart from each other and connected at their ends to the drum heads, annular ring members secured to said girders intermediate the drum heads and wholly supported thereby, and an enclosing decking supported on the rims of the drum heads and ring members.

CLARENCE J PETERSON. 

